Gas extracting apparatus



May 14, 1957 P. J. MOORE GASEXTRACTING APPARATUS Filed Oct.- 14, 1955INVENTOR. .PEENELL rz M0025,

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GAS EXTRAtITlNG APPARATUS Pernell J. Moore, Houston, Tex., assignor toNational Lead Company, New York, N. Y., a corporation of New JerseyApplication October 14, 1953, Serial No. 385,950

2 Claims. (Cl. 183-25) This invention relates to the art of loggingwells during drilling, particularly by the detection of gas in the mudfluids used therein, and more particularly to an improved process anddevice for obtaining samples of gas from such mud.

The art of obtaining a continuous log of sub-surface formationspenetrated by the bit during the course of drilling for oil and gas by acontinuous inspection of the drilling fluid and cuttings for shows ofoil and gas therein has been considerably refined and improved in recentyears. The general procedure has been fully described in the literatureand is currently widely practiced. Thus, it is not deemed necessary togive details of the overall method here.

An important feature of this type of logging is concerned with removingat least a portion of any gas present in the circulating drilling mud,and subjecting such gas samples to a determination of the presence ofcombustible hydrocarbons therein. The usual method of procedure here isto arrange a trap, generally baffled, at or near the exit of the flowline of the drilling well, so that such gas samples can be collected,while permitting the continuous flow of the mud therethrough.

None of the traps now in use is completely satisfactory. What is desiredis extraction of the gas contained in the mud in a fashion independentof such variables of the latter as density, viscosity, and particularlygel strength. Additionally, an extractive device which operatesindependently of the flow rate of the mud through the circulating systemis a desideratum of great importance.

An object of this invention is to provide a device and process forextracting gas from drilling mud for sampling purposes.

Another object of the invention is to provide a device which not onlysamples mud for gas but propels the mud through the device in a fashionsubstantially independent of the physical conditions of the mud and ofthe flow rate of the mud in the circulating system.

Another object of the invention is to provide a gas sampling process andapparatus for muds which will enable the extraction of even smallquantities of gas from exceedingly thick muds.

Another object of the invention is to provide a gas sampler which issimple in construction, economical in operation, and effective for thepurposes indicated.

Other objects of the invention will appear as the description thereofproceeds.

In the drawing,

Fig. 1 is a perspective view of a device conforming to the presentinvention; a portion has been cut away to show the interior of saiddevice.

Fig. 2 is a cross-section of the device shown in Fig. 1, taken at thelevel of A-A'.

Fig. 3 shows a typical installation of the device of the invention inthe mud circulating system of an oil well.

Figs. 4 and 5 show respectively the side and bottom views of analternative impeller-agitator construction which may be used in thedevice.

Coming now to a detailed description of one embodiment of the inventionwhich is illustrative and serves to show a mode of action employed inthe inventon, reference is had to Fig. 1. In this figure, 10 designatesa casing of generally cylindrical form which may conveniently be madefrom brass or steel tubing. This casing is closed at top and bottom bydisks 11 and 12 respectively. Disk 12 is perforated by a generallycentral hole 13, which serves as an inlet for mud. In the interior ofthe casing, and generally concentric within it, is positioned animpeller-agitator shaft 14, which is connected to and driven by a motor15 which may be conveniently an electric motor. Reference character 16indicates a power lead for this motor. The impeller shaft 14 carries animpeller-agitator portion 17, which may be, as shown in the figure, asingle rod symmetrically disposed with respect to the shaft 14 and atright angles thereto. Alternatively, a plurality of rods may be used asis illustrated in Figs. 4 and 5.

Referring again to Fig. 1, the side of the casing 10 thereof isperforated, near the center thereof, by a threaded opening in which issecured an outlet spout 18, which may conveniently be an ordinary streetelbow. The top disk it bears a gas outlet 19, which is conveniently ashort piece of pipe welded to the disk. A fitting 20 and a hose 21 areshown attached thereto for conduction of the gas to any desireddetection means.

In use, the device illustrated in Fig. l is partially immersed in thedrilling mud to be sampled. This is most conveniently accomplished byplacing the device in a portion of the mud ditch, when possible near aweir which maintains a more or less constant level of mud. Such anarrangement is shown diagrammatically in Fig. 3, wherein 30 are thesides of the mud ditch or flume, 31 is the mud flowing through, 32 is asubmerged weir, and 33 is a clamp which serves to attach the device it]to the side of the ditch at a suitable height. It will he observed thatthe device is positioned so that the outlet of the outlet spout 18 isslightly above the normal level of mud in the ditch.

In operation, the shaft 14 is rotated at a suitable speed, which may be,for example, 1725 R. P. M., by means of the electric motor 15. Beforethe motor is started, it will be observed that with the devicepositioned as shown in Pig. 3, the mud will have sought its own levelwithin the casing 16, by reason of the opening in the bottom and theside opening. Rotation of the shaft with its associatedimpeller-agitator rod or rods brings about a number of effects inco-action. In the first place, a strong vortex action is created whichlowers very considerably the level of the mud in the central-mostportion of the casing 10, and causes a corresponding rise in the levelclose to the wall. This in turn results in a gentle pumping action,whereby mud is drawn up through the central hole 13 and dischargedthrough the side opening. This pump action is facilitated and indeed ismaintained remarkably constant by virtue of the fact that the mud iskept beaten down in gel strength by the action of the impeller-agitatorrod or rods. Simultaneously air is beaten into the mud and out again asa result of the vortex action in combination with the rod. This causesthe air in the upper portion of the casing 10 to be maintained inequilibrium with the gas content of the mud. A slight suction applied atthe gas sampling tube or pipe 1? serves to withdraw air continuously andat the constant rate from the upper portion of the casing it so that itcan be subjected to any desired test. The wellknown hot-wire detector issuitable for this purpose and has been quite generally described in theliterature. Maintaining the side outlet 18 above the level of the mud inthe ditch allows freedom of access of air to the inside of the cylinder.

Excellent results have been obtained in actual field trials of devicescorresponding to this invention'and more particularly to the deviceillustrated by Fig. 1 and explained hereinabove. For the first time inthe art, both large and small gas shows have been uniformly'pres'entedto the detecting means regardless of mud characteristics and mud flow. a

It will be seen that the invention accomplishes its objects, especiallyin the provision of a device to perform the desired results. It will beunderstood that I do not limit myself to the particular mechanicalembodiments shown, but that modifications and changes may be made in thedevice and in the implacement and operation thereof, all within thescope of the herein-described invention and the appended claims.

Having described the invention, what I claim is:

1. In a device for extracting gas from well drilling mud, at timescontaining minute quantities thereof, While the mud is in circulationduring drilling, the combination of a top, a bottom and a side wall ofgenerally cylindrical form defining a substantially closed, singlecompartment, hollow chamber constructed to be immersed with its axisvertical to a fraction of its depth in said mud, said bottom having acentral opening therethrough of a diameter less than that of the sidewall, an opening in said side Wall of limited area positioned to beabove the immersion level, a gas outlet passage communicating with theupper portion of said chamber, a vertical shaft positioned centrally inat least the lower portion of said chamber, an impeller-agitatorconsisting of at least one horizontally disposed rod afiixed to saidshaft near and above said bottom and being of a length not less than thediameter of said central opening, and means to rotate said shaft atsufficiently high speed to produce a vortex action in the body of liquidin said chamber to circulate liquid from said central opening outthrough said side wall opening.

2. A device for extracting gas from well drilling mud circulating duringdrilling operations, in combination, a cylindrical container having aside wall and top and bottom closure plates defining a singlecompartment, means to support said container with its axis vertical andimmersed to a minor fraction of its depth in said mud, said side wallhaving an opening therein above the level of immersion, said bottomplate having a central aperture therein, a gas outlet tube extendingthrough a Wall of said compartment and terminating therein above thelevel of said opening, an impeller-agitator having at least one beaterelement disposed close to and above the said bottom plate, symmetricalin respect to the center of said aperture, longer than the diameter ofthe aperture and having its ends equally spaced from the plane of theplate, and means to rotate said impeller agitator about the axis of saidcontainer at a speed sufficient to produce a vortex in the body of mudin the compartment capable of lifting it for discharge through said sidewall opening.

References Cited in the file of this patent UNITED STATES PATENTS835,126 Wilson Nov. 6, 1906 2,294,827 Booth Sept. 1, 1942 2,341,169Wilson et al. Feb. 8, 1944 2,514,690 Bliss et al July 11, 1950 2,704,658Gordon Mar. 22, 1955

2. A DEVICE FOR EXTENDING GAS FROM WELL DRILLING MUD CIRCULATING DURINGDRILLING OPERATIONS, IN COMBINATION, A CYLINDRICAL CONTAINER HAVING ASIDE WALL AND TOP AND BOTTOM CLOSURE PLATES DEFINING A SINGLECOMPARTMENT, MEANS TO SUPPORT SAID CONTAINER WITH ITS AXIS VERTICAL ANDIMMERSED TO A MINOR FRACTION OF ITS DEPTH IN SAID MUD, SAID SIDE WALLHAVING AN OPENING THEREIN ABOVE THE LEVEL OF IMMERSION, SAID BOTTOMPLATE HAVING A CENTRAL APERTURE THEREIN, A GAS OUTLET TUBE EXTENDINGTHROUGH A WALL OF SAID COMPARTMENT AND TERMINATING THEREIN ABOVE THELEVEL OF SAID OPENING, AN IMPELLER-AGITATOR HAVING AT LEAST ONE BEATERELEMENT DISPOSED CLOSE TO AND ABOVE THE SAID BOTTOM PLATE, SYMMETRICALIN RESPECT TO THE CENTER OF SAID APERTURE, LONGER THAN THE DIAMETER OFTHE APERTURE AND HAVING ITS ENDS EQUALLY SPACED FROM THE PLANE OF THEPLATE, AND MEANS TO ROTATE SAID IMPELLER-AGITATOR ABOUT THE AXIS OF SAIDCONTAINER AT A SPEED SUFFICIENT TO PRODUCE A VORTEX IN THE BODY OF MUDIN THE COMPARTMENT CAPABLE OF LIFTING IT FOR DISCHARGE THROUGH SAID SIDEWALL OPENINGS.